Improvement in dooe-seehfgs



I iamrks lj injwwvml E0014 I m'thassas GHARLES BURN HAM, OF. PHILADELPHIA, PENNSYLVANIA.

' Letters Pateitt o. 72,449, dated'December 24, 1867.

IMPROVEMENT 11v noon-srmufes.

TO ALL WHOM IT MAY conceals:

Be it known that I, CHARLES BURNHAM, of the city and county of Philadelphia, and State of Pennsylvania,

have invented a. new and useful Improved Method of Adjusting and Securing Springs to Doors for the purpose of making them self-closing; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and letters of reference markedthereon.

The nature of my invention consists in an improvement in that class of door-closing springs which are operated by the torsion of an elastic rod, whose axis is coincident or approximates to the axis of the hinges upon which the door swings, and is for the purpose of giving greater facility of adjustment, without increasing the expense of production or weakening the-essential working parts. p

The door-spring, which is the subject of my invention, consists of an elastic cylindrieal or prismatic rod, A, fastened by one end to a bearing, B, secured tothedoor-frame in such a manner that the end thus fastened cannot be rotated, and guided or steadied by the eyes G C, fitting loosely upon the rod A, so that the rod A may rotate freely in them, which eyes 0 C-may be fastened upon either the door or frame. The other end of the rod A is inserted through a notched or toothed wheel, D, which wheel D is supported in a cup-bearing, E,

fastened to the door, and partaking of the motion of the door in swinging open or shut upon its hinges. Intothe notches of the wheel D there fits a wheel or segment of a wheel, turning upon a central axis, G, whichmay be, for convenience, one of the screws for attaching the cup-bearing to the door. This wheel G is of such form that the different portions of the edge, successively engaging in the notches of the wheel D, act like a tangentscrew in a worm-wheel, and hold the wheel Di any intermediate adjustment, more minute 'than'can' be done by moving the wheel D through the entire space from one notch to anotherl The edge of the wheel G may be made spiral, so as to be in fact a single turn of an endless screw, or they may be made in gradations or steps, as shownin Figure 2', and, forgreater convenience in liberating the wheel D, and permit it to "turn freely so as to render the door-spring inoperative, when desired, the wheel G may have an opening or notch left in the edge, 'so that, when the notched sideis presented to the wheel D, it will rotate freely in the notch. I

4 It will be readily apparent that the precise arrangementherein described may be varied, and the same result accomplished, by modifications equivalent mechanically to that already described. Thus the fixture containing the notched wheel Dmay be placed either'upon the door or frame, provided the fixture upon the other end is not attached to the same part as the wheel-fixture, and itis equally clear that, instead of a wheel or segment with a spiralor graduated edge, as shown, in fig.' 2, a straight bar, with an obliqueor graduated edge, may be made to effect the-same object, if engaged in the notched wheel D, a

The cupped fixture, shown in Figure 1, is made with cavities-on both sides thereof, so as it may be used for either a right or left door. i

The advantage realized in this device is superior nicety of adjustment of the force or tension of the spring,

which cannot be obtained by increasing the number of notches in the wheel D, because the wheel would not then be strong enough in the teeth, and the diameter of the wheel D is limited by the close proximity of the axial line of most door-hinges to the plane of the door.

What I claim as my invention, and desire to secure as such by Letters Patent, is- 1. In combination'with a rod or torsion door-spring, the screw-threaded cam or worm G, or an equivalent thereof, as described, engaging with the notched burr or wheel D on the end of the said'torsion-rod, for the pur pose of graduating the tension thereof, substantially as described;

2.-In combination with the above, the double socket or receiver E, for support-ingthe notched wheel D,

substantially as described. i t

cuss. BURNHAM.

Witnesses:

S, LLOYD WAGAND, Josn'rn G. TAIT. 

